This project will use animal models to study the early stages of external eye infections by viruses (Herpes simplex virus, adenovirus), bacteria (Hemophilus, pneumococcus) or Chlamydia with the use of electron microscopy and standard microbiologic techniques. These pathogenetic studies will focus on the role of the corneal and conjunctival epithelial cell in resisting infection with these organisms. Systematic experiments will be carried out in both non+immune and immune animals to study the differences in epithelial cell infection and inflammatory cellular response. Cytochemical staining will be carried out to evaluate the role of lysosomal enzymes in these infectious processes. The same electron microscope techniques will be applied to the early diagnosis of some inflammatory eye diseases in man: Herpes simplex infections of the cornea, bacterial corneal ulcers, acute follicular conjunctivitis and others. Corneal specimens available at the time of corneal transplant surgery in patients with herpetic keratitis will be examined for the presence of herpes virus. It will be possible to correlate these observations on patients with those made in animal models. These studies of animal models will lead to a better understanding of the role of conjunctival and corneal epithelial cells in the pathogenesis of infections of the external eye. The studies of human eye infections will be aimed at early diagnosis and will also confirm certain phases of the pathogenesis studies in animals.